MS-LS3-1: Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

Clarification Statement: Emphasis is on conceptual understanding that changes in genetic material may result in making different proteins.

By the end of grade 8. In sexually reproducing organisms, each parent contributes half of the genes acquired (at random) by the offspring. Individuals have two of each chromosome and hence two alleles of each gene, one acquired from each parent. These versions may be identical or may differ from each other. In addition to variations that arise from sexual reproduction, genetic information can be altered because of mutations. Though rare, mutations may result in changes to the structure and function of proteins. Some changes are beneficial, others harmful, and some neutral to the organism.

Evidence Statements

MS-LS3-1

1. Components of the model

   1. Students develop a model in which they identify the relevant components for making sense of a given phenomenon involving the relationship between mutations and the effects on the organism, including:

      1. Genes, located on chromosomes.

      2. Proteins.

      3. Traits of organisms.

2. Relationships

   1. In their model, students describe the relationships between components, including:

      1. Every gene has a certain structure, which determines the structure of a specific set of proteins.

      2. Protein structure influences protein function (e.g., the structure of some blood proteins allows them to attach to oxygen, the structure of a normal digestive protein allows it break down particular food molecules).

      3. Observable organism traits (e.g., structural, functional, behavioral) result from the activity of proteins.

3. Connections

   1. Students use the model to describe that structural changes to genes (i.e., mutations) may result in observable effects at the level of the organism, including why structural changes to genes:

      1. May affect protein structure and function.

      2. May affect how proteins contribute to observable structures and functions in organisms.

      3. May result in trait changes that are beneficial, harmful, or neutral for the organism.

   2. Students use the model to describe that beneficial, neutral, or harmful changes to protein function can cause beneficial, neutral, or harmful changes in the structure and function of organisms.